l6o The Deccent of Man. Paut I. 



confirmed by Prof. Kupffer. M. Kovalevsky writes to me from 

 Naples, that he has now carried these observations yet further ; 

 and should his results be well established, the whole will form a 

 discovery of the very greatest value. Thus, if we may rely on 

 embryology, ever the safest guide in classification, it seems that 

 we have at last gained a clue to the source whence the Vertebrata 

 were derived.^" We should then be justified in believing 

 that at an extremely remote period a group of animals existed, 

 resembling in many respects the larvsB of our present Ascidiana, 

 which diverged into two great branches— the one retrograding in 

 development and producing the present class of Ascidians, tlie 

 other rising to the crown and summit of the animal kingdom by 

 giving birth to the Vertebrata. 



We have thus far endeavoured rudely to trace the genealogy 

 of the Vertebrata by the aid of their mutual aflSnities. We will 

 now look to man as he exists; and we shall, I think, be able 

 partially to restore the structure of our early progenitors, during 

 successive periods, but not in due order of time. This can be 

 effected by means of the rudiments which man still retains, by 

 the characters which occasionally make their appearance in him 

 through reversion, and by the aid of the principles of morphology 

 and embryology. The various facts, to which I shall here allude, 

 have been given in the previous chapters. 



The early progenitors of man must have been once covered 

 with hair, both sexes having beards ; their ears were probably 

 pointed, and capable of movement ; and their bodies were pro- 

 vided with a tail, having the proper muscles. Their limbs and 

 bodies were also acted on by many muscles which now only 

 occasionally reappear, but are normally present in the Quadru- 

 mana. At this or some earlier period, the great artery and nerve 

 of the humerus ran through a supra-condyloid foramen. The 

 intestine gave forth a much larger diverticulum or caecum than 

 that now existing. The foot was then prehensile, judging from 

 the condition of the great toe in the foetus ; and our progenitors, 

 no doubt, were arboreal in their habits, and frequented some 

 warm, forest-clad land. The males had great canine teeth, which 



2^ But I am bound to add that " peut produire la disposition fonda- 



some competent judges dispute this " mentale du type vert^bri5 (I'ex- 



couclusion ; for instance, M. Giard, *' istence d*une corde dorsale) chea 



in a series of papers in the ' Archives " un invert^br^ par la seule con- 



de Zoologie Experimentale,' for 1872. " dition vitale de I'adaptation, 



Nevertheless, this naturalist re- " et cette simple possibility du 



marlcs, p. 281, "L'cganisationde la "passage supprime I'abimc entrf 



" larve ascidienne en dehors de " les deux sous-rfegnes, encore bien 



** toute hypothfese et de toutethebrie, " qu'en ignore par ou le passag* 



" aous rrtonl re comiLtiiit la nature *' s'est fait en r^aliti " 



